Create and preview texture in Blender 2.80b?
The workflow of creating materials &amp; textures is different for each render engine.
The tutorial you are trying to follow explains Blender Internal renderer workflow, it is fast and easy, but this renderer is no longer supported in Blender 2.8, so this method is no more applicable.

This means - if you want to learn how to create materials and texture your models in 2.8, you have to watch tutorials focused on 2.8 and it's supported renderers (Cycles / Eevee).